Liquid crystal devices can be easily controlled in state of alignment of liquid crystal molecules, thus can be variably controlled in optical property, and are therefore being considered to be used as liquid crystal lenses.
In order to increase a lens power, such as the variable range of focal distances, in such a liquid crystal lens, the liquid crystal layer needs to be increased in thickness. However, if the liquid crystal layer is increased in thickness, there arises a problem of reduced speed of response of the optical property of the liquid crystal lens to the voltage applied thereto.
Patent Literatures 1 and 2 propose a method in which a liquid crystal layer is divided into two sublayers by the intervention of a thin glass sheet therebetween to reduce the effective thickness of the liquid crystal layer to half.
Patent Literature 3 describes that, with the use of a thin glass sheet having a thickness of about 100 μm or less, for example, 70 μm, as in the method described in Patent Literatures 1 and 2, such a thin glass sheet is very likely to be broken to make the production process of the liquid crystal lens difficult. However, a method described in Patent Literature 3 has still not solved the problem that with the use of a thin glass sheet the thin glass sheet is likely to be broken in the production process.